[kube-prometheus-stack] Prometheus storageSpec Helm values ignored

Describe the bug a clear and concise description of what the bug is.

When deploying Prometheus with Helm the storageSpec in the values.yaml seems to be ignored. I specify 50Gi but a volume of 8Gi is created (did several runs with cleanup in between)..

See below for the values.yaml part related to Prometheus. What am I missing?

What's your helm version?

version.BuildInfo{Version:"v3.15.3", GitCommit:"3bb50bbbdd9c946ba9989fbe4fb4104766302a64", GitTreeState:"clean", GoVersion:"go1.22.5"}

What's your kubectl version?

Client Version: v1.30.3 Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3 Server Version: v1.30.1+k3s1

Which chart?

rometheus-community/prometheus

What's the chart version?

helm.sh/chart: prometheus-25.27.0

What happened?

When deploying Prometheus with Helm the storageSpec in the values.yaml seems to be ignored. I specify 50Gi but a volume of 7.8Gi is created. The values.yaml entries for Prometheus are:

prometheus:
  enabled: true
  ingress:
    enabled: false
  serviceMonitor:
    selfMonitor: true
  prometheusSpec:
    ## Settings affecting prometheusSpec
    ## ref: https://github.com/prometheus-operator/prometheus-operator/blob/main/Documentation/api.md#prometheusspec
    replicas: 1
    replicaExternalLabelName: "replica"
    ruleSelectorNilUsesHelmValues: false
    serviceMonitorSelectorNilUsesHelmValues: false
    podMonitorSelectorNilUsesHelmValues: false
    probeSelectorNilUsesHelmValues: false
    image:
      registry: "{{harbor_registry}}"
      repository: prometheus
      tag: v2.54.1
    enableAdminAPI: true
    walCompression: true
    storageSpec:
      volumeClaimTemplate:
        spec:
          storageCLassName: longhorn
          acessModes: ["ReadWriteOnce"]
          resources:
            requests:
              storage: 50Gi

What am I missing?

What you expected to happen?

Expected to get a 50Gi volume as specified.

How to reproduce it?

Apply the Helm chart with the above in the values file.

Enter the changed values of values.yaml?

See above.

Enter the command that you execute and failing/misfunctioning.

helm install prometheus prometheus-community/prometheus -f values.yaml

Anything else we need to know?

No response

prometheus-community / helm-charts